Association of Space Flight With Problems of the Brain and Eyes

Space flight-associated neuroocular syndrome (SANS), characterized by increased optic nerve sheath diameter (ONSD) and globe flattening, is detected in some astronauts. We estimated CSF pressure (p CSF ) during space flight based on published reports 2 and found that SANS was not caused mainly by increased p CSF but rather by brain upward shift (BUS), recently demonstrated in postflight astronauts. Our findings suggest that eyes are portals into effects on the brain during space flight.